Multiple connection plugs are coming to be used on an ever-increasing scale for producing connections between fluid-powered units, fluid supplies and fluid receivers and furthermore for producing connections between fluid logic circuits and sensors and loads used therewith. Such multiple connection plugs are standardized. One useful effect of them is that they take up little space while on the other hand there is less danger of producing a wrong connection in comparison with systems in which separate fluid lines are used.
For producing a connection between standard fluid terminals of connection plugs and the separate, different fluid terminals of the active and passive fluid components, the special geometry and connection position of such components are taken into account by using adapter blocks. Such adapter blocks have fluid connections or terminals on one connection face at standard points while on their other face, opposite thereto, they have connection openings or terminals in line with the geometry of the component used therewith. Between these two faces there are channels in the adapter block for producing the desired connections, such channels more specially being open and uncovered at the face of the adapter block so that the channels have to be covered over by, and fixed tightly against, the component to be worked through the channels, that is to say so that such channels, which in the first place are open on one side, are covered over and in the form of complete ducts.
So far in the prior art, such adapter blocks have been high in price to make. If only a small quantity is produced, the holes of the open channels are produced by machining a solid block of material (as a rule, a thermoplastic or thermosetting resin). Such machining does, however, take many man-hours and require expensive machining systems because of the mechanical properties of the resins used; furthermore, the inner faces or lining faces of the channels are generally rough.
Furthermore, such adapter blocks may only be economically produced by injection molding if large production runs are needed, this being because of the high price of injection molds. Furthermore, if a thermosetting resin is used, a heavy press is needed for shutting the injection mold, and any further machining which may be necessary after molding, for example because of a very complex channel geometry, would be high in price, and the brittle material is likely to be broken. If, on the other hand, a thermoplastic material is used, there is on the hand the shortcoming of uneven shrinkage and furthermore any after-machining which may be necessary is hard to undertake because of the material's being tough.